package com.hmdp.service.impl;

import cn.hutool.core.util.BooleanUtil;
import cn.hutool.core.util.StrUtil;
import cn.hutool.json.JSONObject;
import cn.hutool.json.JSONUtil;
import com.baomidou.mybatisplus.extension.plugins.pagination.Page;
import com.hmdp.dto.Result;
import com.hmdp.entity.Shop;
import com.hmdp.mapper.ShopMapper;
import com.hmdp.service.IShopService;
import com.baomidou.mybatisplus.extension.service.impl.ServiceImpl;
import com.hmdp.utils.CacheClient;
import com.hmdp.utils.RedisConstants;
import com.hmdp.utils.RedisData;
import com.hmdp.utils.SystemConstants;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.cache.CacheManager;
import org.springframework.data.geo.Distance;
import org.springframework.data.geo.GeoResult;
import org.springframework.data.geo.GeoResults;
import org.springframework.data.redis.connection.RedisGeoCommands;
import org.springframework.data.redis.core.StringRedisTemplate;
import org.springframework.data.redis.domain.geo.GeoReference;
import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Transactional;

import javax.annotation.Resource;
import java.time.LocalDateTime;
import java.util.*;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.concurrent.TimeUnit;

/**
 * <p>
 *  服务实现类
 * </p>
 *
 * @author 虎哥
 * @since 2021-12-22
 */
@Service
public class ShopServiceImpl extends ServiceImpl<ShopMapper, Shop> implements IShopService {

    @Autowired
    private StringRedisTemplate stringRedisTemplate;

    @Resource
    private CacheClient cacheClient;

    @Override
    public Result queryById(Long id) {
        //缓存穿透
//        Shop shop = cacheClient
//                .queryWithThrough(RedisConstants.CACHE_SHOP_KEY,id ,Shop.class ,this::getById,RedisConstants.CACHE_SHOP_TTL,TimeUnit.MINUTES);

        //互斥锁解决缓存击穿
//        Shop shop = queryWithMutex(id);
        //逻辑过期解决缓存击穿
        Shop shop = cacheClient
                .queryWithLogicalExpire(RedisConstants.CACHE_SHOP_KEY,id ,Shop.class ,this::getById,10L,TimeUnit.SECONDS);

        if (shop == null) {
            return Result.fail("店铺不存在!");
        }
        //7.返回
        return Result.ok(shop);
    }

    private static final ExecutorService CACHE_REBUILD_EXECUTOR = Executors.newFixedThreadPool(10);

//    public Shop queryWithLogicalExpire(Long id){
//        //1.从redis查询店铺缓存
//        String key =  RedisConstants.CACHE_SHOP_KEY + id ;
//        String shopJson = stringRedisTemplate.opsForValue().get(key);
//
//        //2.判断缓存是否存在
//        if (StrUtil.isBlank(shopJson)) {
//            //3.存在,直接返回
//            return null;
//        }
//
//        //4. 命中,需要先把Json反序列化为对象
//        RedisData redisData = JSONUtil.toBean(shopJson, RedisData.class);
//        JSONObject data = (JSONObject) redisData.getData();
//        Shop shop = JSONUtil.toBean(data, Shop.class);
//        LocalDateTime expireTime = redisData.getExpireTime();
//
//        //5. 判断是否过期
//        if(expireTime.isBefore(LocalDateTime.now())){
//            //5.1 未过期,返回店铺信息
//            return shop;
//        }
//
//        //5.2 已过期,进行缓存重建
//        //缓存重建
//        //6.1 获取互斥锁
//        String lockKey = RedisConstants.LOCK_SHOP_KEY + id;
//        //6.2 判断获取锁是否成功
//        boolean isLock = tryLock(lockKey);
//        if (isLock) {
//            //6.3 获取锁成功,开启独立线程,开始缓存重建
//            CACHE_REBUILD_EXECUTOR.submit(() -> {
//                //重建缓存
//                try {
//                    this.savaShop2Redis(id,5L);
//                } catch (Exception e) {
//                    throw new RuntimeException(e);
//                }finally {
//                //释放锁
//                unlock(lockKey);
//                }
//            });
//        }
//        //6.4返回过期的商铺信息
//
//        //4.不存在.根据id查询数据库
//
//        return shop;
//    }

//    public Shop queryWithMutex(Long id){
//        //1.从redis查询店铺缓存
//        String key =  RedisConstants.CACHE_SHOP_KEY + id ;
//        String shopJson = stringRedisTemplate.opsForValue().get(key);
//
//        //2.判断缓存是否存在
//        if (StrUtil.isNotBlank(shopJson)) {
//            //3.存在,直接返回
//            return JSONUtil.toBean(shopJson, Shop.class);
//        }
//
//        if (shopJson != null) {
//            //返回一个错误信息
//            return null;
//        }
//        //4. 实现缓存重建
//        //4.1 获取互斥锁
//        String lockKey = RedisConstants.LOCK_SHOP_KEY + id;
//        Shop shop = null;
//        try {
//            boolean islock = tryLock(lockKey);
//            //4.2 判断是否获取成功
//            if (!islock) {
//            //4.3 失败,休眠重试
//                Thread.sleep(50);
//                return queryWithMutex(id);
//            }
//
//
//            //4.4 成功.根据id查询数据库
//            shop = getById(id);
//            //模拟重建的延时
//            Thread.sleep(200);
//            //5. 不存在,返回错误
//            if (shop == null) {
//                //将空值写入redis
//                stringRedisTemplate.opsForValue().set(key,"",RedisConstants.CACHE_NULL_TTL, TimeUnit.MINUTES);
//                return null;
//            }
//
//            //6.存在,写入redis
//            stringRedisTemplate.opsForValue().set(key,JSONUtil.toJsonStr(shop),RedisConstants.CACHE_SHOP_TTL, TimeUnit.MINUTES);
//
//
//        } catch (InterruptedException e) {
//            throw new RuntimeException(e);
//        }finally {
//            //7. 释放互斥锁
//            unlock(lockKey);
//        }
//        //8.返回
//        return shop;
//    }


//    public Shop queryWithThrough(Long id){
//        //1.从redis查询店铺缓存
//        String key =  RedisConstants.CACHE_SHOP_KEY + id ;
//        String shopJson = stringRedisTemplate.opsForValue().get(key);
//
//        //2.判断缓存是否存在
//        if (StrUtil.isNotBlank(shopJson)) {
//            //3.存在,直接返回
//            return JSONUtil.toBean(shopJson, Shop.class);
//        }
//
//        if (shopJson != null) {
//            //返回一个错误信息
//            return null;
//        }
//
//
//        //4.不存在.根据id查询数据库
//        Shop shop = getById(id);
//
//        //5. 不存在,返回错误
//        if (shop == null) {
//            //将空值写入redis
//            stringRedisTemplate.opsForValue().set(key,"",RedisConstants.CACHE_NULL_TTL, TimeUnit.MINUTES);
//            return null;
//        }
//
//        //6.存在,写入redis
//        stringRedisTemplate.opsForValue().set(key,JSONUtil.toJsonStr(shop),RedisConstants.CACHE_SHOP_TTL, TimeUnit.MINUTES);
//
//        //7.返回
//        return shop;
//    }



    public void savaShop2Redis(Long id , Long expireSeconds) throws InterruptedException {
        //1. 查询店铺信息
        Shop shop = getById(id);
        //2. 封装逻辑过期时间
        RedisData redisData = new RedisData();
        redisData.setData(shop);
        redisData.setExpireTime(LocalDateTime.now().plusSeconds(expireSeconds));
        //3. 写入redis
        stringRedisTemplate.opsForValue().set(RedisConstants.CACHE_SHOP_KEY+id,JSONUtil.toJsonStr(redisData));
    }

    @Override
    @Transactional
    public Result Update(Shop shop) {
        Long id = shop.getId();
        if (id ==null) {
            return Result.fail("店铺id不能为空");
        }
        //1.更新数据库
        updateById(shop);
        //2.删除缓存
        stringRedisTemplate.delete(RedisConstants.CACHE_SHOP_KEY + id);

        return Result.ok();
    }

    @Override
    public Result queryShopByType(Integer typeId, Integer current, Double x, Double y) {
        // 1.判断是否需要根据坐标查询
        if (x == null || y == null) {
            // 不需要坐标查询，按数据库查询
            Page<Shop> page = query()
                    .eq("type_id", typeId)
                    .page(new Page<>(current, SystemConstants.DEFAULT_PAGE_SIZE));
            // 返回数据
            return Result.ok(page.getRecords());
        }

        // 2.计算分页参数
        int from = (current - 1) * SystemConstants.DEFAULT_PAGE_SIZE;
        int end = current * SystemConstants.DEFAULT_PAGE_SIZE;

        // 3.查询redis、按照距离排序、分页。结果：shopId、distance
        String key = "shop:geo" + typeId;
        GeoResults<RedisGeoCommands.GeoLocation<String>> results = stringRedisTemplate.opsForGeo() // GEOSEARCH key BYLONLAT x y BYRADIUS 10 WITHDISTANCE
                .search(
                        key,
                        GeoReference.fromCoordinate(x, y),
                        new Distance(5000),
                        RedisGeoCommands.GeoSearchCommandArgs.newGeoSearchArgs().includeDistance().limit(end)
                );
        // 4.解析出id
        if (results == null) {
            return Result.ok(Collections.emptyList());
        }
        List<GeoResult<RedisGeoCommands.GeoLocation<String>>> list = results.getContent();
        if (list.size() <= from) {
            // 没有下一页了，结束
            return Result.ok(Collections.emptyList());
        }
        // 4.1.截取 from ~ end的部分
        List<Long> ids = new ArrayList<>(list.size());
        Map<String, Distance> distanceMap = new HashMap<>(list.size());
        list.stream().skip(from).forEach(result -> {
            // 4.2.获取店铺id
            String shopIdStr = result.getContent().getName();
            ids.add(Long.valueOf(shopIdStr));
            // 4.3.获取距离
            Distance distance = result.getDistance();
            distanceMap.put(shopIdStr, distance);
        });
        // 5.根据id查询Shop
        String idStr = StrUtil.join(",", ids);
        List<Shop> shops = query().in("id", ids).last("ORDER BY FIELD(id," + idStr + ")").list();
        for (Shop shop : shops) {
            shop.setDistance(distanceMap.get(shop.getId().toString()).getValue());
        }
        // 6.返回
        return Result.ok(shops);
    }
}
